如何创建接受可变数量参数的 Java 方法? [英] How can I create a Java method that accepts a variable number of arguments?

问题描述

例如，Java 自己的 String.format() 支持可变数量的参数.

For example, Java's own String.format() supports a variable number of arguments.

String.format("Hello %s! ABC %d!", "World", 123);
//=> Hello World! ABC 123!

如何制作自己的接受可变数量参数的函数?

How can I make my own function that accepts a variable number of arguments?

后续问题:

我真的想为此创建一个方便的快捷方式:

I'm really trying to make a convenience shortcut for this:

System.out.println( String.format("...", a, b, c) );

这样我就可以把它称为不那么冗长的东西:

So that I can call it as something less verbose like this:

print("...", a, b, c);

我怎样才能做到这一点?

How can I achieve this?

推荐答案

你可以写一个方便的方法:

You could write a convenience method:

public PrintStream print(String format, Object... arguments) {
    return System.out.format(format, arguments);
}

但是正如你所看到的，你只是简单地重命名了format(或printf).

But as you can see, you've simply just renamed format (or printf).

以下是您可以使用它的方法:

Here's how you could use it:

private void printScores(Player... players) {
    for (int i = 0; i < players.length; ++i) {
        Player player = players[i];
        String name   = player.getName();
        int    score  = player.getScore();
        // Print name and score followed by a newline
        System.out.format("%s: %d%n", name, score);
    }
}

// Print a single player, 3 players, and all players
printScores(player1);
System.out.println();
printScores(player2, player3, player4);
System.out.println();
printScores(playersArray);

// Output
Abe: 11

Bob: 22
Cal: 33
Dan: 44

Abe: 11
Bob: 22
Cal: 33
Dan: 44

请注意，还有类似的 System.out.printf 方法，其行为方式相同，但如果您查看实现，printf 只会调用 format，所以你也可以直接使用format.

Note there's also the similar System.out.printf method that behaves the same way, but if you peek at the implementation, printf just calls format, so you might as well use format directly.

• 可变参数
• PrintStream#format(String format, Object... args)
• PrintStream#printf(String format, Object... args)

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